Container Cleaning in Food Processing Operations

FAPC-110
Container Cleaning in Food Processing Operations
Timothy J. Bowser
Food Processing Engineer
Introduction
Thinking about food contamination and responding appropriately to ensure safe food is a crucial part of food processing operations. Containers are a convenient and attractive means of packaging
products; they also protect food from environmental influences and
damage during distribution. Rigid and semi-rigid containers made
of a wide variety of materials are filled with product and securely
closed. In some cases, the heated food product is used to sterilize
the container and closure after filling, or a post-fill sterilization
process is implemented, such as a hot-water bath or pressure cook.
Before filling, however, the container should be cleaned to remove
soil, foreign objects, and chemical contaminants.
Container cleaning and inspection is an important step in food
packaging operations. According to current Good Manufacturing
Practices (Code of Federal Regulations, Title 21, Parts 100, 110,
and 113), containers must be clean. Many small- and medium-scale
food processors regard container cleaning as an unnecessary step
since containers are received in a clean condition and are handled
and inspected individually before, during, and after filling. Cracked,
damaged, soiled, contaminated or otherwise unsuitable containers
are manually removed from the filling operation. However, as automation and the volume of processing increases, it becomes difficult
to rely only on visual inspection.
The process of cleaning food containers, even when they are
new, is indispensable to ensure a safe product. Empty food contain-
ers can harbor foreign materials such as insects and pieces of glass
or plastic. Sterilizing food containers (for example, by irradiation)
without cleaning them eliminates biological hazards but may leave
physical and chemical hazards in the container that affect the safety
of the food product. When consumers discover foreign materials in
a product, the results may include a loss of confidence in the manufacturer, sales reductions, product recalls, and lawsuits. Therefore, a
system to clean containers and improve the safety of food products
should be established.
Container-cleaning Machines
Food containers can be cleaned using a variety of available
equipment. Container-cleaning machines are designed to clean the
inside and/or the outside of containers using water, a water-based
cleaning compound, air, steam, vacuum, or a combination. A typical container-cleaning process is outlined in Figure 1. An example
of a continuous container-cleaning machine is shown in Figure 2.
Containers are continuously conveyed into the washer, cleaned, and
discharged at the opposite end of the machine. A continuous glass
container washer is shown in Figure 3. The glass washer includes
a tempering zone to prevent thermal shock and glass breakage. An
example of an over-the-conveyor continuous cleaner is given in
Figure 4. The containers are held captive in the disk and are cleaned
with an air or steam blast as they are inverted. A common method
used to clean plastic containers is inversion and rinsing with pressur-
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Figure 1. Typical container-cleaning process.
Oklahoma Cooperative Extension Service • Division of Agricultural Sciences and Natural Resources
ized, ionized air. Figure 5 shows a “gripper” conveyor that holds the
plastic container captive for inversion and cleaning operations.
Dishwashers, rack washers or pan washers (Figure 6) can also
be used to clean containers in a batch process. Batch washers may
be an inexpensive alternative to continuous container cleaning
equipment. Batch washers allow additional process flexibility for
product changes, stop and start situations, and may be used for postpasteurization of finished products, if storage space and handling
are not obstacles.
Selecting Container Cleaning Equipment
Several options and brands of container cleaning equipment are
available. The ideal cleaning system for a food processor depends
on, but is not limited to, factors such as:
• Versatility – the type and quantity of items to be washed
or cleaned on a single line
• Desired cleaning time
• Capacity – the combination of options that lets the processor achieve optimum productivity levels
• Expenses – water, compressed air, vacuum, cleaning chemicals, maintenance, operation, and energy source (e.g., gas,
oil, or electric)
• Facility – space limitations on the overall size and shape
of the cleaning system
• Budget – expected return on investment (ROI)
• Container – special handling or other considerations
• Safety – operator, product, and environmental hazards
For additional information on selecting and purchasing equipment used for food processing, read the OSU Extension Fact Sheet
FAPC-102 by Bowser (1999).
Figure 2. Continuous
container cleaner, SJ
Industries, Inc.
1.
2.
3.
4.
Pre-soak
Pre-jet
Main caustic
Post-caustic
Design of a Container Cleaning System
A container-cleaning system can be designed to clean both the
inside and outside surfaces of a container, or merely the inside. A
wide range of equipment is available, from fully automated, highspeed continuous systems to manual, batch operations. Equipment
may be off-line, mounted on an existing conveyor, or freestanding
with feed and discharge conveyors.
Draining and rinse time, temperature, flow rate, chemical
concentration, and water pressure may be regulated. The electrical
installation should be watertight. The machine should be constructed
of stainless steel to resist corrosion, and components and supports
should be designed for ease of cleaning. The machine should be
adjustable to accommodate the range of container dimensions for
the given production line. In addition, the machine should be flexible enough to accommodate containers that may be considered
for future products. If desired, the wash liquid can be collected
in a holding tank for recycling. When batch washers are used, the
containers must be placed into racks and fed into the dishwasher.
Adequate space and facility must be included for rack loading for
both manual and automatic operations.
Table 1 is a partial listing of companies that manufacture and/or
supply container-cleaning machines. Contact the companies and
talk to other processors that are performing container cleaning.
Evaluate product features and find out what works well for other
processors. Web sites with packaging related information such
as http://www.packexpo.com, http://www.packworld.com, http:
//www.foodexplorer.com, and http://www.thomasregister.com
could be valuable sources of information in selecting an appropriate container-cleaning system.
5.
6.
7.
8.
Warm water 1
Warm water 2
Cold water
Fresh water
Figure 3. Glass container washer,
Krones Corporation, model
Lavatec KEK.
Figure 4. Over-conveyor
cleaner, McBrady
Engineering Company,
model Orbit 100.
Figure 6. Batch container
cleaner, Hobart Corporation,
model CPW-80A.
Figure 5. Plastic container held captive in a
“gripper conveyor,” Ambec Corporation.
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Table 1. List of companies and contact information of container cleaning manufacturers/suppliers*.
*
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Oklahoma State University and FAPC do not endorse any specific company.
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110-4